PURPOSE: To obtain a sufficient quakeproof strength with a small-sized constitution, by fixing a device main body to the base through a plane plate-shaped member and a quakeproof supporting member.

CONSTITUTION: A hole for fixing due to a bolt 11 is provided in a proper position of a plane steel material 7 which should be placed on a free access floor 5, and a through hole for a fixing bolt 28 is formed in a position of the floor 5 corresponding to this hole. A quakeproof supporting member B is inserted between the floor 5 and a base 12, and a plane steel material 21 is placed on the base 12, and the fixing bolt 28 is engaged with the through hole formed in the floor 5 by a long nut 27, and the level of the pole brace part is so adjusted that the upper end part of an upper brace 29 is connected to the lower face of the floor 5. A hole for a base bolt 31 is provided in the base 12 through the lower end part of a lower brace 30 and the plane steel material 21, and the bolt 31 is fixed to the base 12 by screwing, and the lower end part of the brace 30 is fixed together with the plane steel material 21 to the base 12.